Reactions of some maize hybrids to different nitrogen rates [Bazi melez misir çeşitlerinin artan azot dozlarina tepkilerinin saptanmasi]

In this pot experiment, reaction of five different maize genotypes grown in Çukurova Region to different rates of nitrogen were measured. Responses of the genotypes employed to different rates of nitrogen were measured using uptake of nitrogen, root and top dry matter yield, number of leaves, plant height and other nutrient contents of the plant and the intetactions among the plant characterictics were examined and interpreted. Total top dry matter yield, number of leaves, plant height, root development and percent calcium contents of the all genotypes increased as the rates of nitrogen increased. P and Mn contents and levels of percent K, Mg. Zn, Fe and Cu in the genotypes were found to be different among the genotypes at 5 % and 1 % leaves as the rates of nitrogen increased, respectively. There was no significant differences in terms of nitrogen contents of the plant among the genotypes as the application rates of nitrogen increased. However, it was observed that the genotype XL.72.AA used the applied nitrogen effectively. On the other hand, nitrogen uptake was found highest when the rate of applied nitrogen was the lowest and the nitrogen absorption rate with genotype XL.72.AA was highest at the lowest nitrogen rate

Diversity Assessment of Turkish Maize Landraces Based on Fluorescent Labelled SSR Markers

Landraces of maize represent a valuable genetic resource for breeding and genetic studies. Since 1970, landraces have been collected from all over Turkey, but the genetic diversity represented in this collection is still largely unknown. In this study, a sample of 98 landraces sampled from 45 provinces of Turkey was assessed genotypically at 28 simple sequence repeat (SSR) loci and phenotypically for 19 morphological traits. The landraces varied significantly for all the latter traits. A total of 172 SSR alleles were detected, giving a mean of 6.21 alleles per locus. The genetic distance between pairs of landraces ranged from 0.18 to 0.63, with a mean of 0.35. Positive and negative correlation exists among different morphological and agronomic traits. Positive association among different traits showed that improvement of one character may simultaneously improve the other desired trait. Based on UPGMA dendrogram and Neighbor-Net (NNET) analyses from both morphological traits and SSR data, respectively, it is obvious that maize landraces from the same geographical region were often placed in different clusters, indicating that grouping based on genetic parameters was not closely related to the geographic origin. The wide diversity present in Turkish maize landraces could be used as genetic resource in designing maize breeding program for developing new cultivars adapted to different geographic and climatic conditions, and may also contribute to worldwide breeding programs. © 2011 Springer-Verlag.Firat University Scientific Research Projects Management Unit: ZF2004BAP17 TOVAG-104O186Acknowledgement We thank the Menemen gene bank (Aegean Agricultural Research Institute, Izmir, Turkey) for the kind provision of landrace seed stocks. The authors express their gratitude to TÜBİTAK (The Scientific and Technological Research Council of Turkey, TOVAG-104O186) and University of Cukurova, Scientific Research Projects Unit (ZF2004BAP17) for their financial support

Effect of salinity stress on dry matter production and ion accumulation in hybrid maize varieties

The salt stress tolerance of 19 hybrid maize (Zea mays L.) varieties was tested in nutrient solution during the early growth stage under controlled environmental conditions. For the salt stress treatment, sodium chloride (NaCl) was applied to nutrient solution at a concentration of 250 mM for 6 days before the harvest. Plants were harvested after 17 days of growth and analyzed for shoot and root dry matter production, severity of leaf damage (necrotic patches on older leaves), and the concentrations of potassium (K), sodium (Na) and calcium (Ca) in the roots and shoots. The varieties differed greatly in their response to the NaCl treatment. The development time and severity of leaf symptoms caused by 250 mM NaCl were varied markedly among the varieties. Based on the severity of leaf symptoms, the varieties Maverik and C.7993 were classified as the most tolerant and sensitive varieties, respectively. The decreases in the shoot dry matter production as a consequence of the NaCl treatment were higher than the decreases in root growth. There was also a marked genotypic variation in concentrations of K, Ca and Na in roots and particularly in shoots. The higher salt tolerance in maize varieties based on the severity of leaf symptoms was associated with significantly lower Na concentrations in shoots. The K/ Na and Ca/Na ratios were significantly greater in most of the tolerant varieties. The most sensitive variety, C.7993, contained a 4-fold greater Na concentration in shoots than the most tolerant variety, Maverik. The varieties RX.9292 and MF.714 also contained very high Na in shoots and showed severe toxicity symptoms on leaves. Besides Maverik, P.3394 and P.3223, with their low shoot Na concentrations, could also be considered tolerant varieties. Under salt treatment significant correlations were found between K/Na ratios and shoot dry matter production (r = 0.541***), K/Na ratios and leaf damage (r = -0.411***), and Ca/Na ratios and shoot dry matter production (r = 0.444***). The results indicate the existence of a large genotypic variation in tolerance to NaCl toxicity in maize that should be exploited in breeding programs aiming to develop maize varieties with high NaCl tolerance during the early growth stages. Among the ions measured, shoot Na concentration was a reliable screening parameter in ranking varieties for their tolerance to salt stress. © TÜBİTAK

Relation of root tensile strenght to vertical root-pull resistance and some agronomical characteristics in maize [Misir bitkisinde kök sökülme direnci ölçümü ve bazi tarimsal özellikler ile i·lişkilerinin saptanmasi]

Examining of root system of maize is quite difficult and it takes a lot of time under field conditions. Because of this, the study abciut maize reformation on root properties are not enough. Using the new method to determine root magnitude is an important subject for maize breeders in recent years. The value of root pulling resistance that is measured by using computer aided machines, can give some information about root system of plant. In this study, an important variation was obtained between 15 hybrid maize varieties due to the rciot pulling resistance. The root pulling resistance of genotypes changes between 835.4 and 1723.9 N/per plant. It was obtained that there are no significantcorrelation coefficients between root pulling resistance with plant height, first ear height, stem diameter and ear weight per plant

The effect of green manure crops of legumes on grain yield and some agronomical characters of maize grown on different nitrogen doses [Degisik azot dozlarinda yetistirilen misir bitkisinde tane verimi ve bazi tarimsal ozelliklere bazi yesil gubre baklagil bitkilerinin etkisi]

In this research, the effect of green manure crops of legumes such as horsbean, mixture of horsbean+vetch, alexandrie klee, fenugreek on grain yield and some agronomical characters of maize grown on different nitrogen doses (0, 12 and 24 kg N da-1) were investigated. Also, dry matter of nodule, root and biomass of above ground and total amount of N were determined. According to the resulting two years, the total amount of N fixed to the soil by the way of nodule, root and biomass of above ground was between 27.5-38.8 kg da-1. Also it was determined that maize could be grown using less nitrogen fertilizer after the application of green manure. The grain yields of maize applied 24 kg N da-1 and 12 kg N da-1 after the growth of wheat were 1055 kg da-1 and 1141 kg da-1 respectively. The grain yields of maize applied 12 kg N/da-1 after the growth of mixture of horsbean+vetch, fenugreek and horsbean and alexandria klee were 1141, 1122, 1124, 1207 kg da-1 respectively. It was determined that after the application of green manure, maize could be sown earlier than the crop system of wheat+maize cultivated commonly in Cukurova region